Date: Wed, 13 Jan 2021 17:59:17 -0800 From: John-Mark Gurney <jmg@funkthat.com> To: "Andrey V. Elsukov" <bu7cher@yandex.ru> Cc: Lutz Donnerhacke <lutz@donnerhacke.de>, freebsd-net@freebsd.org, Hans Petter Selasky <hps@selasky.org> Subject: Re: FreeBSD does not reply to IPv6 Neighbor Solicitations Message-ID: <20210114015917.GR31099@funkthat.com> In-Reply-To: <065eaff7-35bd-0cd3-f68f-849be2178574@yandex.ru> References: <mailman.93.1609761601.91504.freebsd-questions@freebsd.org> <E9644A2A-6C5F-48C9-AD2D-13BC7FB2E534@gromit.dlib.vt.edu> <20210105031528.GA91534@admin.sibptus.ru> <00a101d6e33b$96edf0c0$c4c9d240$@donnerhacke.de> <20210105104650.GA7688@admin.sibptus.ru> <00b601d6e35a$115a4a20$340ede60$@donnerhacke.de> <20210112022525.GN31099@funkthat.com> <95be49e2-56cc-cf3f-3515-8f13f14ddbad@yandex.ru> <20210112213707.GP31099@funkthat.com> <065eaff7-35bd-0cd3-f68f-849be2178574@yandex.ru>
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Andrey V. Elsukov wrote this message on Wed, Jan 13, 2021 at 11:42 +0300: > On 13.01.2021 00:37, John-Mark Gurney wrote: > >> when this will happen again, it would be nice to make sure that NS > >> packets hit the IP stack. E.g. with attached dtrace script. > > > > Ok, I ran the dtrace script when I reproduced the problem, and it did > > not produce any output. > > > > These are effectively what the script does: > > 9) configure inet6 addresses on ure and bge (duplicating the addresses > > already configured) > > Does it mean that you just reconfigure address without removing it? It > looks like the problem, that was discussed here > https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=233535 Yeah, I guess it is the same... > > bge0: > > inet6 fe80::12e7:c6ff:fexx:xxxx%bge0 scopeid 0x2 > > mldv2 flags=2<USEALLOW> rv 2 qi 125 qri 10 uri 3 > > group ff01::1%bge0 scopeid 0x2 mode exclude > > mcast-macaddr 33:33:00:00:00:01 > > group ff02::1%bge0 scopeid 0x2 mode exclude > > mcast-macaddr 33:33:00:00:00:01 > > group ff02::1:ffxx:xxxx%bge0 scopeid 0x2 mode exclude > > mcast-macaddr 33:33:ff:xx:xx:xx > > > > so, I made things works, and ran ifmcstat again, and this time it has > > an additional group in the output: > > [...] > > bge0: > > inet6 fe80::12e7:c6ff:fexx:xxxx%bge0 scopeid 0x2 > > mldv2 flags=2<USEALLOW> rv 2 qi 125 qri 10 uri 3 > > group ff02::1:ff00:c43c%bge0 scopeid 0x2 mode exclude > > mcast-macaddr 33:33:ff:00:c4:3c > > group ff01::1%bge0 scopeid 0x2 mode exclude > > mcast-macaddr 33:33:00:00:00:01 > > group ff02::1%bge0 scopeid 0x2 mode exclude > > mcast-macaddr 33:33:00:00:00:01 > > group ff02::1:ffxx:xxxx%bge0 scopeid 0x2 mode exclude > > mcast-macaddr 33:33:ff:xx:xx:xx > > > > and the tcpdump output: > > 21:10:53.938655 IP6 fc00:b5d:41c:7e37::7e37 > ff02::1:ff00:c43c: ICMP6, neighbor solicitation, who has fc00:b5d:41c:7e37::c43c, length 32 > > 21:10:55.001428 IP6 fc00:b5d:41c:7e37::7e37 > ff02::1:ff00:c43c: ICMP6, neighbor solicitation, who has fc00:b5d:41c:7e37::c43c, length 32 > > Since ff02::1:ff00:c43c%bge0 is not configured in first case, IP stack > just ignores NS messages and they don't hit ND6 code. > > In the PR 233535 the problem was reproducible with MLDv1, so if you > disable MLDv2 will it work (to reduce possible scope of problematic code)? > > net.inet6.mld.v2enable=0 I just tested this, and it does not fix the problem for me. Do I need to reboot or something? If I set it to 0, the bug still appears, and also the ifmcstat has the line: mldv2 flags=2<USEALLOW> rv 2 qi 125 qri 10 uri 3 is there something else that needs to be done to disable mldv2? -- John-Mark Gurney Voice: +1 415 225 5579 "All that I will do, has been done, All that I have, has not."
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